PERPENDICULAR MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To properly control the amount of oxide contained in a magnetic layer for controlling crystal grains and its segregation structure for securing low noise characteristic in the granular magnetic layer consisting of the ferromagnetic crystal grain and a nonmagnetic grain boundary containing the oxide surrounding it as a main body. SOLUTION: In a perpendicular magnetic recording medium having the granular magnetic layer and a nonmagnetic underlayer consisting of metal or alloy having a hexagonal close-packed crystal structure, the ferromagnetic crystal grains consist of an alloy containing at least Co and Pt, and the volume of the nonmagnetic grain boundary containing the oxide as the main body is≥15% and≤40% of the volume of the whole magnetic layer. COPYRIGHT: (C)2007,JPO&INPIT